1-O-alkylglycerols for pharmaceutical or veterinary use for preserving and/or improving sperm

ABSTRACT

The invention relates to new uses for 1-O-alkylglycerols and notably such of those compounds naturally present in fish liver oils and notably the liver oils of sharks. More precisely, the invention relates to the use of such compounds for the production of medicines for human use to combat sterility, to produce alimentary adjuvants for veterinary use that permit an increase in fertilization yields in animal breeding, to produce sperm storage adjuvants and to produce factors that encourage the mobility of spermatozoons during in vitro fertilization.

The invention relates to both the pharmaceutical and the veterinaryfields.

More precisely, the invention relates to reproduction and notably findsapplication in the field of sterility treatment for human beings and inthe field of improving fertility in animals. The invention also findsapplication in the field of in vitro fertilisation and assistedprocreation.

The objective of this invention is to provide new uses for knowncompounds in which they play a role within the field of reproduction.More precisely, one of the objectives of this invention is to provide ause of such compounds in combating sterility in men.

Another objective of the invention is to describe new uses of suchcompounds in increasing the fertility of breeding animals and hence inimproving the productivity of such animal breeding.

Yet another objective of this invention is to disclose the new use ofsuch compounds to encourage in vitro fertilisation and also to permitimproved storage of sperm during the carrying out of methods of assistedprocreation.

These various objectives and others that will become apparent in whatfollows are achieved thanks to the invention which relates to a medicinefor human use to combat masculine sterility, characterised in that itcomprises at least one 1-O-alkylglycerol compound. According to thisinvention, in effect it has been discovered that such compounds allowone to increase in a significant way the motor functions of thespermatozoons and hence they can be used to combat certain cases ofmasculine sterility.

According to a preferred variant, such a medicine is designed to beadministered by the oral route in such a way as to have the advantage ofbeing easily absorbed and hence of facilitating the treatment for whichit has been prescribed.

The invention also relates to an alimentary adjuvant for veterinary useintended to increase fertilisation yields in animal breedingcharacterised in that it includes at least one such 1-O-alkylglycerolcompound. This new use is also based on the potential of such compoundsto encourage the motor functions of the spermatozoons.

The invention also relates to a conservation adjuvant for spermcharacterised in that it comprises at least one 1-O-alkylglycerol. Sucha compound allows the fertilisation power of the stored sperm to beimproved which permits an improvement in the chances of success whencarrying out assisted procreation procedures.

Finally, the invention also relates to a factor that encourages themobility of the spermatozoons during in vitro fertilisationcharacterised in that it comprises at least one 1-O-alkylglycerolcompound. Such a factor is capable of improving the chances of successin the operation of in vitro fertilisation.

Preferably, the 1-O-alkylglycerol compound used for all these newapplications is of natural origin. Alkylglycerols are present in smallquantities in several natural products. They are found in thehaematopoietic organs particularly in the bone marrow and also inrelatively large concentration in maternal milk. However it is incertain fish liver oils and in particular in the liver oils of certainspecies of shark that these etherlipids are to be found in greatestabundance. These oils contain more than 50% alkylglycerols.

This is the reason why the preferred source of the compound being usedis fish liver oil and advantageously shark liver oil. The inventiontherefore provides a path for the economic development of this type ofproduct that stems from the fishing industry and which traditionally isa low cost product.

Preferably said 1-O-alkylglycerol is chosen from the group made up by18:1 alkyl-1-glycerol, 16:1 alkyl-1-glycerol and 16:0 alkyl-1-glycerol.These three compounds are, in effect, those which are present in thegreatest quantities in the shark liver oils. This is particularly so for18:1 alkyl-1-glycerol.

The activity of the 1-O-alkylglycerols in the context of the usesdescribed above results from the fact that such compounds are theprecursors of Platelet Activating Factor (PAF).

Platelet Activating Factor (PAF) is a general term that groups togetherthe derivatives of glycerophosphocholine (GPC). The alkyl-PAF is themost active compound and its general structure is1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine. The number of carbonatoms and the degree of unsaturation in the alkyl chain can vary withoutmodifying in any significant way its biological activity. Thealkenyl-PAFs or plasmalogenic PAFs(1-O-alk-1′-enyl-2-acetyl-sn-glycero-3-phosphocholine) and the acyl-PAFs(1-acyl-2-acetyl-sn-glycero-3-phosphocholine) are much less powerfulthan the alkyl-PAFs. PAF has a wide range of biological activity at verylow concentrations (from 10⁻¹⁰ to 10⁻⁹M). Initially identified as amediator released by the leucocytes and capable of activating the bloodplatelets, it has been established that PAF plays a role in the field ofreproduction. Production of PAF has been shown to occur during ovulation(Abisogun A.O. et al., (1989) Science 243:381-383). It has also beendemonstrated that PAF increases the motor function of the spermatozoonsof various animal species and of man and that the treatment of thespermatozoons by PAF increases their power of fertilisation of ovocytesof the rabbit and of the mouse (Roudebush et al., (1993) J. Assis.Reprod. Gen. 10:91-94; Brijinder et al., (1989) Am. J. Obstet. Gynecol.161:1714-1717).

It should be noted however that in these various pieces of work, therehas not been any interest taken in the possibility of using theprecursors of PAF for uses such as those proposed by the invention.

It should equally be noted that it has already been suggested in thestate of the technology that PAF itself be used in order to try toimprove the properties of stored sperm. However such a use had ended infailure because of the delicate handling required due to the very highbiological activity of this product.

With the aim of confirming the activity of the 1-O-alkylglycerols forthe specific applications mentioned above, various tests have beencarried out.

A first series of tests has been carried out so as to verify that thesecompounds are integrated into the spermatozoons.

For this purpose, different samples of human sperm, boar sperm andrabbit sperm were placed under incubation for 24 hours at 35° C., in thepresence of an extract from shark liver oil that contained a mixture of1-O-alkylglycerols labelled with tritium (said samples comprising 54 to65% of 18:01 alkyl-1-glycerol, 5 to 15% of 16:1 alkyl-1-glycerol and 5to 10% of 16:0 alkyl-1-glycerol as well as other alkylglycerols insmaller quantities). These tests were carried out using said mixture ata concentration of 10⁻⁵ Mol/l of 1-O-alkylglycerols.

Following this incubation, the lipid fraction of the spermatozoons wasextracted and the radioactivity of this fraction was measured. Theresults show that:

about 12% of the initial radioactivity is found in the total lipids ofthe boar spermatozoons

about 10% of the initial radioactivity is found in the total lipids ofthe rabbit spermatozoons

about 5% of the initial radioactivity is found in the total lipids ofthe human spermatozoons.

These results demonstrate well the cellular integration of the1-O-alkylglycerols according to the invention in the spermatozoons.

A more precise study has shown that a small fraction of thisradioactivity was incorporated into the phospholipids (phosphatidylcholine and phosphatidyl ethanolamine), namely 0.1% in each of the boarand rabbit classes and less than 1% for man. In the neutral lipids, avery small fraction is metabolised in the form of1-alkyl-2-3-diacylglycerols (less than 0.1%) for the three species. Theremainder of the radioactivity is found in the native form of the1-O-alkylglycerols.

A second series of tests has been carried out and has allowed one todemonstrate that the mobility of boar spermatozoons was found to havebeen significantly increased after an incubation of from 24 to 96 hoursin the presence of the alkylglycerol mixture mentioned above at the rateof 10⁻⁵ Mol/l of 1-O-alkylglycerols.

What is claimed is:
 1. A method of treating masculine sterility byincreasing sperm mobility, the method comprising administering at leastone 1-O-alkylglycerol compound selected from the group consisting of16:0 alkyl-1-glycerol, 18:1 alkyl-1-glycerol, 16:1 alkyl-1-glycerol to amammalian subject.
 2. A method according to claim 1, wherein said1-O-alkylglycerol compound is administered orally.
 3. A method ofincreasing fertilization yields in breeding animals by increasing spermmobility, the method comprising administering at least one1-O-alkylglycerol compound selected from the group consisting of 16:0alkyl-1-glycerol, 18:1 alkyl-1-glycerol, and 16:1 alkyl-1-glycerol as aveterinary alimentary adjuvant to a mammalian subject.
 4. A method ofstoring sperm to preserve their mobility, the method comprising using astorage adjuvant comprising at least one 1-O-alkylglycerol compoundselected from the group consisting of 16:0 alkyl-1-glycerol, 18:1alkyl-1-glycerol, and 16:1 alkyl-1-glycerol, wherein said storageadjuvant is administered to a sperm sample.
 5. A method for increasingmotor function of spermatozoa during in vitro fertilization comprisingadministering a factor comprising at least on 1-O-alkylglycerol compoundselected from the group consisting of 16:0 alkyl-1-glycerol, 18:1alkyl-1-glycerol, and 16:1 alkyl-1-glycerol, wherein said factor isadministered to a mammalian subject.
 6. A method according to claim 1,wherein said 1-O-alkylglycerol compound is of natural origin.
 7. Amethod according to claim 6, wherein said 1-O-alkylglycerol compoundcomes from fish liver oil.
 8. A method according to claim 7, whereinsaid 1-O-alkylglycerol compound comes from shark liver oil.
 9. A methodaccording to claim 3, wherein said 1-O-alkylglycerol compound is ofnatural origin.
 10. A method according to claim 9, wherein said1-O-alkylglycerol compound comes from fish liver oil.
 11. A methodaccording to claim 10, wherein said 1-O-alkylglycerol compound comesfrom shark liver oil.
 12. A method according to claim 4, wherein said1-O-alkylglycerol compound is of natural origin.
 13. A method accordingto claim 12, wherein said 1-O-alkylglycerol compound comes from fishliver oil.
 14. A method according to claim 13, wherein said1-O-alkylglycerol compound comes from shark liver oil.
 15. A method forincreasing motor function of spermatozoa according to claim 5, whereinsaid 1-O-alkylglycerol compound is of natural origin.
 16. A method forincreasing motor function of spermatozoa according to claim 15, whereinsaid 1-O-alkylglycerol compound comes from fish liver oil.
 17. A methodfor increasing motor function of spermatozoa according to claim 16,wherein said 1-O-alkylglycerol compound comes from shark liver oil. 18.A method of treating masculine sterility by increasing sperm mobility,the method comprising administering a composition in an effectiveamount, wherein said composition comprises at least one1-O-alkylglycerol compound selected from the group consisting of: 16:0alkyl-1-glycerol, 18:1 alkyl-1-glycerol, and 16:1 alkyl-1-glycerol,wherein said 1-O-alkylglycerol compound is derived from fish liver oilto a patient in need thereof.
 19. A method of increasing fertilizationyields in breeding animals by increasing sperm mobility, the methodcomprising administering a composition in an effective amount whereinsaid composition comprises at least one 1-O-alkylglycerol compoundselected from the group consisting of: 16:0 alkyl-1-glycerol, 18:1alkyl-1-glycerol, and 16:1 alkyl-1-glycerol, wherein said1-O-alkylglycerol compound is derived from fish liver oil to an animalin need thereof.
 20. A method of preserving the motor function ofspermatozoa during the storage and conservation thereof, the methodcomprising contacting sperm with a composition wherein said compositioncomprises at least one 1-O-alkylglycerol compound selected from thegroup consisting of: 16:0 alkyl-1-glycerol, 18:1 alkyl-1-glycerol, and16:1 alkyl-1-glycerol, wherein said 1-O-alkylglycerol compound isderived from fish liver oil.
 21. A method of preserving the motorfunction of spermatozoa during in vitro fertilization comprisingcontacting spermatozoa with a composition wherein said compositioncomprises at least one 1-O-alkylglycerol compound selected from thegroup consisting of: 16:0 alkyl-1-glycerol, 18:1 alkyl-1-glycerol, and16:1 alkyl-1-glycerol, wherein said 1-O-alkylglycerol compound isderived from fish liver oil.